I don't have an extruder in my studio, but I do like to play with the one at Portland Pottery. Theirs is a North Star, which has the ability to make hollow extrusions - pipes of different shapes. This herb tray was a long, square pipe cut into four bits, with added slab bottoms, and a hex-shaped pipe cut along one side and folded in at the ends. A student pointed out that this would also work if the pots had no bottoms, and both tray and pots were filled with soil.
There are holes in the bottom of each little pot to allow for drainage, and the whole set is unglazed: I thought the earthy look was appropriate, and I find plants don't like a glazed interior, even when there is drainage.
I've planted thyme and cilantro in this set, and basil and oregano in other planters.
I sell these sets, sans dirt & seeds, for $48.
Ceramic Materials and Process Workshop
3 hours ago